There is no such thing as common sense, and the fact that you think you have it despite having zero clue about how MM works, proves you shouldn't be in this conversation.
Further, tesla also monetizes stuff exactly like this so you don't have to go an aftermarket route. Also, the idiot parts changers at the dealer should have checked the hardware due to being off angle before moving to software. There was literally zero reason for them to reflash the truck. You clearly have never worked in the industry or you would know that. Any tech that isn't a complete mouthbreather would have checked the hardware given it would have been the likely cause. The software never comes into play unless there is a motor that tilts the camera.
Lastly, for mm to not apply, the "aftermarket" solution would have to cause the problem he was having. It didn't. This would be like putting 35s on the truck and gm saying we have to trash those because we put crappy lifters in your motor. A doesn't equal B in any way, shape or form.